@ebrewer,
In the case of bootstrap tabs, since the second tab is not displayed initially, the second chart is rendered when the shown.bs.tab event is fired by bootstrap using the chart.render method as shown in the code-snippet below,
$('#bs-tab2').on("shown.bs.tab",function(){
ct1();
$('#bs-tab2').off();//to remove the binded event after initial rendering
});
Here is the working code for the same.
—
Adithya Menon
Team CanvasJS